"Military research programs throughout history have made significant contributions to medicine and, in particular, to vaccine development. These efforts have been driven primarily by the effects of infectious disease on military conflicts: smallpox devastated the Continental Army in 1776, as well as troops on both sides of the United States Civil War; typhoid fever was common among soldiers in the Spanish American War. More person-days were lost among U.S. soldiers in malaria-endemic regions to malaria than to bullets throughout the entire 20th century; indeed, malaria continues to sap military strength into the current century."